<ul class="panel panel-default nav nav-sidebar weixin">
    <li class="item">
        <a data-toggle="collapse" data-parent="#navbar" 
          href="#collapsew">
            公众号管理
        </a>
    </li>
    <div class="nav nav-sidebar panel-collapse collapse " id="collapsew" >
        <li class="active"><a href="#"></a></li>
    </div>
</ul>